Imaging Placebo Responses in the Brain
Over the past few years, there have been an increasing number of studies investigating placebo responses, with sophisticated techniques, such as positron emission tomography (PET), functional magnetic resonance imaging (fMRI), electroencephalography (EEG), magnetoencephalography (MEG) and recording from single neurons in awake patients. Most of our knowledge about the mechanisms that underlie the placebo effect comes from the field of pain and analgesia. However, the widespread interest in understanding the nature of the placebo effect within the neuroscience community has provided important insights into its neural mechanisms in other medical conditions, including Parkinson’s disease, depression, and drug addiction. Here, we review the literature that deals with placebo effects and brain imaging, and emphasize the contributions of macro- and micro-mapping studies to our understanding of the underlying brain processes. The knowledge of the placebo mechanisms across different systems and diseases makes it possible for us to identify the top-down processes that modulate the course of symptoms and diseases, as well as the specific action of drugs and the therapeutic response to their administration.
KeywordsPositron Emission Tomography Irritable Bowel Syndrome Anterior Cingulate Cortex Placebo Effect Placebo Response
This work was supported by grants from Istituto San Paolo di Torino and Regione Piemonte.
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